USS Carl Vinson off the coast in Danang on March 5.Photographer: Linh Pham/AFP via Getty Images

This week’s visit by a U.S. aircraft carrier to Vietnam -- the first since the war -- highlights a growing relationship between the former enemies that has blossomed even as the Philippines, a long-time American ally, gets closer to China.

The USS Carl Vinson arrived off the central city of Danang on Monday for a five-day visit along with two escort ships carrying some 6,000 sailors and aviators. The crew will meet with their Vietnamese counterparts, visit victims of Agent Orange, and participate in a soccer match and a concert.

The visit comes as China makes progress toward a deal with the Philippines to jointly explore for oil and gas in disputed parts of the South China Sea, a move that would leave Vietnam more isolated in pushing back. Hanoi’s leaders have rejected China’s claims as a basis for joint development, and have stepped up ties with the U.S., Australia and India to hedge against Beijing’s rise.

Tensions have risen in recent years as China has built up its naval presence, most visibly with a plan to put half-a-dozen aircraft carriers in the world’s oceans. In 2014, China’s move to send an exploration oil rig into waters contested with Vietnam triggered deadly anti-China riots and clashes at sea between coast guard boats.

“The government didn’t back down in 2014 and that played very well,” said Collin Koh Swee Lean, a research fellow at the S. Rajaratnam School of International Studies in Singapore. “I don’t see Vietnam changing its approach. The more the Philippines is seen bending toward China, the more Vietnam is concerned not to be seen doing the same thing.”

Philippine President Rodrigo Duterte has shifted toward China since taking power in 2016, attracting billions of dollars in investment as he downplayed his nation’s legal victory over Beijing in the territorial disputes. On Monday, Duterte’s spokesman Harry Roque said the Philippines and China need a treaty before any joint exploration can take place.

In Vietnam, public opinion is decidedly in favor of the Americans. A 2017 Pew opinion poll found 84 percent of Vietnamese view the U.S. favorably, compared with just 10 percent for China.

Daniel Kritenbrink

Photographer: Hoang Dinh Nam/AFP via Getty Images

“The visit marks an enormously significant milestone in our bilateral relations and demonstrates U.S. support for a strong, prosperous and independent Vietnam,” Daniel Kritenbrink, the U.S. ambassador to Vietnam, told reporters in Danang. The U.S. and Vietnam have “gone from former enemies to close partners,” he said.

‘Red Line’

President Donald Trump’s visit to Vietnam in November laid the groundwork for the aircraft carrier visit, Vietnamese Foreign Ministry spokeswoman Le Thi Thu Hang said in a statement. It will contribute to maintaining peace, security and stability in the region, she said.

While the U.S. takes no formal position on the disputes between China and the other claimants in the South China Sea, it regularly makes so-called freedom of navigation operations to demonstrate the right to fly and sail through what it considers to be international waters and airspace.

Trump during the APEC CEO Summit in Danang in Nov. 2017.

Photographer: SeongJoon Cho/Bloomberg

Defense ties between the U.S. and Vietnam expanded under President Ba­rack Obama. His administration lifted a decades-long embargo on lethal arms sales to Vietnam in 2016, just over two decades after relations were normalized.

Crowds Watching

“The will of the Vietnamese people on this issue is very united, strong and clear,” said Le Dang Doanh, an economist and former Vietnam government adviser. “Vietnam has demonstrated goodwill toward China, but there are limits. If China crosses Vietnam’s red line, Vietnam must defend its position. The people in Vietnam strongly want the defense of its territory.”

The Nimitz-class carrier, bristling with about 60 fighter jets, on Monday docked about half a mile off Danang, attracting thousands of Vietnamese who lined cliffs and bridges to get a glimpse.

“It’s great for us to have such a ship here,” Nguyen Van Hieu, a 57-year-old Danang taxi driver who served in the Vietnam People’s Army during border clashes with China in the 1980s, said of the aircraft carrier. “It’s evidence that the U.S. and Vietnam are getting much closer and that can help us balance our relationship with China.”